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3 years ago

Mark bought 12 boxes of paper clips and 10 packages of index cards for a

Mathematics

1 answer:

Nata [24]3 years ago

8 0

Answer:

paper clips = $1.85

index cards = $3.95

Step-by-step explanation:

Mark

12 paper clips = x

10 index cards = y

$61.70 total

Janice

15 paper clips = x

7 index cards = y

$55.40 total

12x + 10y = 61.70

15x + 7y = 55.40

*** you want to cancel out one of the letters

(12x + 10y = 61.70) * -7

(15x + 7y = 55.40) * 10

-84x -70y = -431.9

150x + 70y = 554.0

-84x -70y = -431.9

66x + 0 = 122.1

66x = 122.1

x = 122.1 ÷ 66

x = 1.85

plug it back in

15(1.85) + 7y = 55.40

27.75 + 7y = 55.40

7y = 55.40 - 27.75

7y = 27.65

y = 27.65 ÷ 7

y = 3.95

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3 years ago

Solve this system of linear equations. Separate

Gelneren [198K]

Answer:

x 2 y -4

Step-by-step explanation:

13x = -54 -20y give it is A

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7 0

3 years ago

5(x+7)+2(y-1)when x=7 and y=2

balu736 [363]

Answer: 72

Step-by-step explanation:

First plug in 7 for x

5(14)

Then multiply

Next plug 2 in for y

2(1)

Multiply

Lastly, add 70 and 2 together.

72.

Hope this helps.

5 0

3 years ago

Read 2 more answers

Write the equation of the line that passes through the points (-6,5) and (3,−5). Put your answer in fully reduced point-slope fo

elena55 [62]

Answer:

$\displaystyle y-5=-\frac{10}{9}(x+6)$

Or:

$\displaystyle y+5=-\frac{10}{9}(x-3)$

Step-by-step explanation:

We want to write the equation of a line that passes through the points (-6, 5) and (3, -5) in point-slope form.

Point-slope form is given by:

$y-y_1=m(x-x_1)$

Thus, first, we need to find the slope. We can use the slope formula:

$\displaystyle m=\frac{\Delta y}{\Delta x}=\frac{(-5)-(5)}{(3)-(-6)}=\frac{-10}{9}=-\frac{10}{9}$

Next, we can use either of the two given points. I'll use (-6, 5). So, let (-6, 5) be (<em>x₁, y₁</em>). Substitute:

$\displaystyle y-(5)=-\frac{10}{9}(x-(-6))$

Or, fully simplified:

$\displaystyle y-5=\frac{-10}{9}(x+6)$

Using the other point, we will acquire:

$\displaystyle y-(-5)=-\frac{10}{9}(x-(3))$

Or, simplified:

$\displaystyle y+5=-\frac{10}{9}(x-3)$

8 0

3 years ago

Write the equation in slope intercept form of a line that goes through (4,9) and has a slope of 1/2

Vedmedyk [2.9K]

Answer:

y = $\frac{1}{2}$ x + 7

Step-by-step explanation:

the equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y-intercept )

here m = $\frac{1}{2}$ , hence

y = $\frac{1}{2}$ x + c ← is the partial equation

to find c substitute (4, 9) into the partial equation

9 = 2 + c ⇒ c = 9 - 2 = 7

y = $\frac{1}{2}$ x + 7 ← equation in slope-intercept form

4 0

3 years ago